xref: /openbmc/linux/kernel/trace/trace_export.c (revision e3b9f1e8)
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * trace_export.c - export basic ftrace utilities to user space
4  *
5  * Copyright (C) 2009 Steven Rostedt <srostedt@redhat.com>
6  */
7 #include <linux/stringify.h>
8 #include <linux/kallsyms.h>
9 #include <linux/seq_file.h>
10 #include <linux/uaccess.h>
11 #include <linux/ftrace.h>
12 #include <linux/module.h>
13 #include <linux/init.h>
14 
15 #include "trace_output.h"
16 
17 #undef TRACE_SYSTEM
18 #define TRACE_SYSTEM	ftrace
19 
20 /*
21  * The FTRACE_ENTRY_REG macro allows ftrace entry to define register
22  * function and thus become accesible via perf.
23  */
24 #undef FTRACE_ENTRY_REG
25 #define FTRACE_ENTRY_REG(name, struct_name, id, tstruct, print, \
26 			 filter, regfn) \
27 	FTRACE_ENTRY(name, struct_name, id, PARAMS(tstruct), PARAMS(print), \
28 		     filter)
29 
30 /* not needed for this file */
31 #undef __field_struct
32 #define __field_struct(type, item)
33 
34 #undef __field
35 #define __field(type, item)				type item;
36 
37 #undef __field_desc
38 #define __field_desc(type, container, item)		type item;
39 
40 #undef __array
41 #define __array(type, item, size)			type item[size];
42 
43 #undef __array_desc
44 #define __array_desc(type, container, item, size)	type item[size];
45 
46 #undef __dynamic_array
47 #define __dynamic_array(type, item)			type item[];
48 
49 #undef F_STRUCT
50 #define F_STRUCT(args...)				args
51 
52 #undef F_printk
53 #define F_printk(fmt, args...) fmt, args
54 
55 #undef FTRACE_ENTRY
56 #define FTRACE_ENTRY(name, struct_name, id, tstruct, print, filter)	\
57 struct ____ftrace_##name {						\
58 	tstruct								\
59 };									\
60 static void __always_unused ____ftrace_check_##name(void)		\
61 {									\
62 	struct ____ftrace_##name *__entry = NULL;			\
63 									\
64 	/* force compile-time check on F_printk() */			\
65 	printk(print);							\
66 }
67 
68 #undef FTRACE_ENTRY_DUP
69 #define FTRACE_ENTRY_DUP(name, struct_name, id, tstruct, print, filter)	\
70 	FTRACE_ENTRY(name, struct_name, id, PARAMS(tstruct), PARAMS(print), \
71 		     filter)
72 
73 #include "trace_entries.h"
74 
75 #undef __field
76 #define __field(type, item)						\
77 	ret = trace_define_field(event_call, #type, #item,		\
78 				 offsetof(typeof(field), item),		\
79 				 sizeof(field.item),			\
80 				 is_signed_type(type), filter_type);	\
81 	if (ret)							\
82 		return ret;
83 
84 #undef __field_desc
85 #define __field_desc(type, container, item)	\
86 	ret = trace_define_field(event_call, #type, #item,		\
87 				 offsetof(typeof(field),		\
88 					  container.item),		\
89 				 sizeof(field.container.item),		\
90 				 is_signed_type(type), filter_type);	\
91 	if (ret)							\
92 		return ret;
93 
94 #undef __array
95 #define __array(type, item, len)					\
96 	do {								\
97 		char *type_str = #type"["__stringify(len)"]";		\
98 		BUILD_BUG_ON(len > MAX_FILTER_STR_VAL);			\
99 		ret = trace_define_field(event_call, type_str, #item,	\
100 				 offsetof(typeof(field), item),		\
101 				 sizeof(field.item),			\
102 				 is_signed_type(type), filter_type);	\
103 		if (ret)						\
104 			return ret;					\
105 	} while (0);
106 
107 #undef __array_desc
108 #define __array_desc(type, container, item, len)			\
109 	BUILD_BUG_ON(len > MAX_FILTER_STR_VAL);				\
110 	ret = trace_define_field(event_call, #type "[" #len "]", #item,	\
111 				 offsetof(typeof(field),		\
112 					  container.item),		\
113 				 sizeof(field.container.item),		\
114 				 is_signed_type(type), filter_type);	\
115 	if (ret)							\
116 		return ret;
117 
118 #undef __dynamic_array
119 #define __dynamic_array(type, item)					\
120 	ret = trace_define_field(event_call, #type, #item,		\
121 				 offsetof(typeof(field), item),		\
122 				 0, is_signed_type(type), filter_type);\
123 	if (ret)							\
124 		return ret;
125 
126 #undef FTRACE_ENTRY
127 #define FTRACE_ENTRY(name, struct_name, id, tstruct, print, filter)	\
128 static int __init							\
129 ftrace_define_fields_##name(struct trace_event_call *event_call)	\
130 {									\
131 	struct struct_name field;					\
132 	int ret;							\
133 	int filter_type = filter;					\
134 									\
135 	tstruct;							\
136 									\
137 	return ret;							\
138 }
139 
140 #include "trace_entries.h"
141 
142 #undef __entry
143 #define __entry REC
144 
145 #undef __field
146 #define __field(type, item)
147 
148 #undef __field_desc
149 #define __field_desc(type, container, item)
150 
151 #undef __array
152 #define __array(type, item, len)
153 
154 #undef __array_desc
155 #define __array_desc(type, container, item, len)
156 
157 #undef __dynamic_array
158 #define __dynamic_array(type, item)
159 
160 #undef F_printk
161 #define F_printk(fmt, args...) __stringify(fmt) ", "  __stringify(args)
162 
163 #undef FTRACE_ENTRY_REG
164 #define FTRACE_ENTRY_REG(call, struct_name, etype, tstruct, print, filter,\
165 			 regfn)						\
166 									\
167 struct trace_event_class __refdata event_class_ftrace_##call = {	\
168 	.system			= __stringify(TRACE_SYSTEM),		\
169 	.define_fields		= ftrace_define_fields_##call,		\
170 	.fields			= LIST_HEAD_INIT(event_class_ftrace_##call.fields),\
171 	.reg			= regfn,				\
172 };									\
173 									\
174 struct trace_event_call __used event_##call = {				\
175 	.class			= &event_class_ftrace_##call,		\
176 	{								\
177 		.name			= #call,			\
178 	},								\
179 	.event.type		= etype,				\
180 	.print_fmt		= print,				\
181 	.flags			= TRACE_EVENT_FL_IGNORE_ENABLE,		\
182 };									\
183 struct trace_event_call __used						\
184 __attribute__((section("_ftrace_events"))) *__event_##call = &event_##call;
185 
186 #undef FTRACE_ENTRY
187 #define FTRACE_ENTRY(call, struct_name, etype, tstruct, print, filter)	\
188 	FTRACE_ENTRY_REG(call, struct_name, etype,			\
189 			 PARAMS(tstruct), PARAMS(print), filter, NULL)
190 
191 bool ftrace_event_is_function(struct trace_event_call *call)
192 {
193 	return call == &event_function;
194 }
195 
196 #include "trace_entries.h"
197